DEVELOPMENT OF ELECTROCHEMICAL PAPER-BASED BIOSENSORS BASED ON CARBONIZED PAPER ELECTRODES FOR THE DETECTION OF CANCER MARKERS

• Grant number: 24/23722-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: November 30, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Analytical Chemistry
• Principal Investigator: Vanessa Neiva de Ataide
• Grantee: Mayara Orneles Silva
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

This research project aims to fabricate low-cost electrochemical biosensors based on carbonized paper electrodes using a CO2 laser machine. The primary purpose of using a CO2 laser in the electrode fabrication process is to promote the photothermal conversion of a non-conductive material (paper) to a conductive material (carbonizedpaper) in a straightforward, fast (seconds), and scalable manner. In this way, the laser carbonization parameters will be studied to achieve an improved electrochemical performance; they include the laser power, the focal distance (height between the laser output and the substrate), and line spacing or resolution. Variations in these parameters can influence the electrode surface chemical composition, such as the presence of oxygenated groups. Thus, the aim is to evaluate how the chemical environment impacts these characteristics on the electrode surface in addition to these experimental parameters. The presence of functional groups is significant when considering electrochemical reactivity, especially in this project's case, which aims to assess the feasibility of biomolecule immobilization. In this sense, after characterizing the chemical, morphological, and structural composition of these electrodes using different techniques (electrochemistry, microscopy, and spectroscopy), the study of various strategies for immobilizing biomolecules (captureantibody) will be carried out, which will consist of i) passive adsorption using protein A and ii) crosslinking with EDC/NHS. The application of the electrochemical biosensors to be developed will be for detecting breast cancer biomarkers, among them the HER-2 protein. Additionally, studies of the biosensor analytical performance will be evaluated, including response range, repeatability, reproducibility, shelf life, detection limit, and study of interfering species. Therefore, this project's purpose is mainly to contribute to advancing the development of analytical devices that can be applied as low-cost diagnostic tests with decentralized analyses (without the need for a laboratory structure).